Firearm rear sight



FIG. 1 is a perspective view of a firearm rear sight showing my new design;

FIG. 2 is a left-side elevation view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a right-side elevation view thereof;

FIG. 5 is a rear elevation view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is bottom plan view thereof.

The broken lines and the areas within them depict portions of the firearm rear sight that form no part of the claimed design. 

CLAIM The ornamental design for a firearm rear sight, as shown and described. 